Compact discs (CDs) are widely used as disc-shaped recording media on which digital data converted from audio data such as a music tune as work data is recorded and which enable reading of the data by optical reproducing means. A CD is a recording medium having a diameter of 12 cm and capable of recording data of not less than 600 MB. On such a CD, digital data is recorded on the basis of a standardized recording format. Based on the standard recording format of the CD, there are provided CD-ROMs on which data to be processed by computers or application software for television games is recorded, CD-Rs which enable writing of data once, CD-RWs which enable rewriting of data, and so on.
As data recording media on which digital data converted from image information of high quality or the like is recorded, DVDs (digital versatile discs) are provided.
CDs and DVDs are recording media which enable mass duplication and mass distribution of data from original discs. CDs and DVDs on which the same work data such as music tunes or video information is recorded have basically the same format, and each of the discs is housed and distributed in a container having a common form or design.
In order to identify so-called package media such that independent recording media having common work data recorded thereon are housed and distributed in respective common containers, serial numbers are printed on or seals having serial numbers printed thereon are attached to the containers housing the recording media or printed matters housed together with the recording media in the containers.
In the case where serial numbers are provided on the containers or the printed matters housed in the containers of the package media as described above, identification to discriminate other recording media of the same type cannot be carried out simply with the recording media themselves. In the case where seals having serial numbers printed thereon are peeled off or the containers or printed matters having serial numbers printed thereon are lost, the correspondence between the serial numbers and the recording media cannot be achieved and the serial numbers themselves cannot be recognized. Moreover, when recording media alone are handed to other people, it is difficult to manage the recording media.
In the case of the conventional package media that are widely distributed, once the package medium is sold to a user, the user can freely use the work data recorded on the recording medium but repeated duplication of the data read out from the recording medium is regulated. Therefore, providing the work data from the user who purchased the package medium to another user via a data distribution system such as the Internet is also regulated.
Moreover, as a method for distributing work data based on the contents such as music tunes, EMD (electronic music distribution) is used, which is a method utilizing the Internet. The work data distributed by this EMD is purchase-type data similar to the package media. The user can freely use the work data but repeated distribution or duplication of the once distributed data is regulated.